NASA Scientific and Technical Aerospace Reports

The use of wind power is in a period of rapid growth worldwide and wind energy systems have emerged as a promising
technology for utilizing offshore wind resources for the large scale generation of electricity Drawing upon the maturity of wind
turbine and floater technologies developed by the wind energy and oil and gas industries, respectively, large offshore wind
energy systems have been developed and are being proposed for operation in offshore areas where environmental restrictions
are less restrictive, large wind resources exist, and open sea areas are available for wind farm development. A fully coupled
dynamic analysis/technique was developed to predict the response of a floating wind turbine system in a stochastic wind and
wave environment This technique incorporated both non-linear wave loading on the submerged floater and the aerodynamic
loading on the wind turbine A tension leg spar buoy was designed to support the wind turbine This design was chosen due
to its relatively small size and hence lower potential cost per wind turbine The system’s tethers were attached to the ends of
spokes which radiated out from the spar cylinder This arrangement of lines and spokes promised to be very stiff in the roll
and pitch modes of motion.
DTIC
Floating; Turbines; Wind Turbines; Windpower Utilization
20040112009 NASA Langley Research Center, Hampton, VA, USA
Experimental Robust Control Studies on an Unstable Magnetic Suspension System
Lim, Kyong B.; Cox, David E.; [1993]; 6 pp.; In English; No Copyright; Avail: CASI; A02, Hardcopy
This study is an experimental investigation of the robustness of various controllers designed for the Large Angle Magnetic
Suspension Test Fixture (LAMSTF). Both analytical and identified nominal models are used for designing controllers along
with two different types of uncertainty models. Robustness refers to maintain- ing tracking performance under analytical
model errors and dynamically induced eddy currents, while external disturbances are not considered. Results show that
incorporating robustness into analytical models gives significantly better results. However, incorporating incorrect uncertainty
models may lead to poorer performance than not designing for robustness at all. Designing controllers based on accurate
identified models gave the best performance. In fact, incorporating a significant level of robustness into an accurate nominal
model resulted in reduced performance. This paper discusses an assortment of experimental results in a consistent manner
using robust control theory.
Author
Magnetic Suspension; Stability; Robustness (Mathematics); Controllers; Mathematical Models
20040120886 Federal Aviation Administration, Washington, DC
Full-Scale Engine Knock Tests of 30 Unleaded, High-Octane Blends
Atwood, D.; Canizales, J.; Sep. 2004; 318 pp.; In English
Report No.(s): PB2004-107307; DOT/FAA/AR-04/25; No Copyright; Avail: CASI; A14, Hardcopy
Effective January 1, 1996, a 1990 Federal Clean Air Act Amendment banned the sale of leaded fuels for on-road vehicles
but exempted the sale of leaded fuels for off-road use, such as aircraft, racing cars, farm equipment, and marine engines. This
has resulted in the general aviation community becoming one of the largest domestic consumers of leaded fuels. With
environmental pressures increasing worldwide against the use of leaded fuels and lead scavenging agents, the future status of
the Environmental Protection Agency exemption for general aviation is uncertain and is increasingly a subject of debate. For
more than a decade, the Federal Aviation Administration (FAA) William J. Hughes Technical Center has worked closely with
aircraft manufacturers, engine manufacturers, petroleum producers, chemical companies, universities, regulatory agencies, and
the Aircraft Owner and Pilot Association through both the Coordinating Research Council (CRC) and the American Society
for Testing of Materials (ASTM) to facilitate the development of a safe, high-octane, unleaded aviation gasoline for spark
ignition, piston aircraft engines.
NTIS
Air Quality; Aircraft Fuels; Crude Oil; Environment Protection
20040120988 NASA Glenn Research Center, Cleveland, OH, USA
Gas Sensors Using SiC Semiconductors and Method of Fabrication Thereof
Hunter, Gary W., Inventor; Neudeck, Philip G., Inventor; July 20, 2004; 18 pp.; In English; Original contains black and white
illustrations
Patent Info.: Filed 6 Feb. 2003; US-Patent-6,763,699; US-Patent-Appl-SN-359940; NASA-Case-LEW-17300-1; No
Copyright; Avail: CASI; A03, Hardcopy
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